High temperature molten salt thermal cells are required for applications in fuses, projectile rockets, bombs, missiles, decoys, jammers and torpedoes. Thermal batteries are reserve-type primary batteries that can be activated by heating with a pyrotechnic heat source such as zirconium and barium chromate powders or mixture of iron powder and potassium perchlorate. Amongst the many molten salt battery systems that have been studied over the past many years, the lithium alloy/metal sulfide cell has shown considerable promise for these applications. Heretofore, these cells have used a lithium alloy (Li-Al) as the anode, an electrolyte of lithium halide-alkali halide mixture (LiCl-KCl eutectic) and a cathode having as the cathode active material a binary metal sulfide of the general formula YS or YS.sub.2 where Y=Fe, Co, or Ni.
Though the binary metal sulfides have been useful as the cathode active materials, it would be desirable to provide cathode active materials with higher thermal stability at higher temperatures, and also provide cathode active materials with higher specific energy densities and higher specific power densities.